Hormones and Weight Loss: What’s the Connection?

If you’re like most Americans age 50-plus, your waistline is six centimeters wider than it was in your 20s or 30s, and the numbers on your scale reflect this, too.

We can all tick off the reasons: genetic predisposition, supersized portions, too much sitting, and not enough moving. But there’s another theory circulating through the weight-loss world: hormonal imbalance.

To suss out whether your hormones are colluding with your fat cells, specific lab testing should be made. Hormones are chemical messengers made by our bodies and they have wide-ranging effects: controlling growth, developing sex organs, directing blood sugar levels, and, yes, influencing body weight, body fat, and muscle mass.

Levels of certain hormones change with age and they can occasionally cause weight gain. For the vast majority of people who are overweight or have obesity, hormones are not the main cause.

According to the leading endocrinologists, here is the complete list of hormones that may affect your body fat (both the gain and loss of it) as you age:

Thyroid Hormones

What they do: The thyroid, a gland that sits in the front of your neck, releases hormones with wide-ranging effects — everything from stimulating fetal growth to regulating heart rate and body temperature to dictating metabolic rate (the rate at which you burn calories).

The body weight connection: If you’re hyperthyroid, like 1.2 percent of Americans, the gland is overactive, secreting too much hormone which gooses metabolism and can lead to a dramatic weight loss. That might sound pretty great, but the condition puts your heart, bones, and eyes at risk.

Nearly 5 percent of Americans (higher rates for those age 60-plus) are hypothyroid, with an underactive gland that produces too little hormone, slowing metabolic rate.

If you have either of these conditions (measured by blood tests for levels of thyroid hormones and thyroid-stimulating hormone — TSH), and your clinician recommends medication (hormone replacement), you’ll probably return to your usual weight if you were hyperthyroid, and if you were hypothyroid, you’ll probably lose a few pounds. But medication is not going to reverse a big weight gain because it’s not likely a major cause of your weight gain, according to leading endocrinologists.


What it does: One of the main sex hormones for women, the hormone triggers puberty in girls and regulates fertility. Estrogen also helps protect the cardiovascular system and bones as well as influences mood.

The body weight connection: Estrogen may affect your shape, nudging fat to the hips and thighs. That’s why, when estrogen levels plummet with menopause, women tend to gain more ‘visceral’ fat that lodges deep in the abdomen. Thyroid experts also state that it isn’t yet clear whether menopause itself makes you gain weight overall.

Because menopause is a natural stage of life and not a disease, there’s usually no need for hormone replacement therapy unless symptoms like hot flashes and insomnia are taking a bite out of your quality of life. However, this is a time to be extra conscientious about nutrition, calorie intake, and exercise to keep visceral fat in check. In excess, this fat raises the risk for heart disease, type 2 diabetes, and other conditions.


What it does: The main sex hormone for men (initiating puberty and fertility and influencing body composition and libido), also affects mood, cardiovascular health, and more.

The body weight connection: Testosterone encourages muscle formation and tamps down body fat. Starting in a man’s 20s and 30s, levels of this hormone naturally drop about 5 to 10 percent per decade. Does this drop drive up body fat? The research isn’t definite on this.

However, in hypogonadism, which is diagnosed by finding a low testosterone level in men with symptoms like low libido, depression, or signs like anemia or osteoporosis, men tend to have a lower percentage of muscle and a higher percent of fat, especially visceral fat, according to endocrinologists.

If your testosterone levels are normal, do nothing. Getting extra hormones probably won’t change body composition and can have harmful side effects such as prostate enlargement and worsening cholesterol. But if you’re diagnosed with hypogonadism, you should consult a doctor about the potential benefits of testosterone treatment. It might take off a few pounds, especially around your midsection, but don’t expect the treatment to completely reverse overweight or obesity in case if your lifestyle and nutrition aren’t healthy enough.


What it is: Leptin is derived from the Greek word for “thin,” because rising levels of this hormone signal the body to shed body fat. Leptin also helps regulate blood sugar, blood pressure, fertility, and more.

The body weight connection: Emitted by fat cells, leptin serves as a recon system, alerting the brain to both gains and losses in body fat. As you pack on more fat, leptin levels rise, dialing down appetite while boosting metabolic rate — which helps put the brakes on weight gain.

Thyroid specialists say that for reasons that are not clear, in people with obesity there’s a breakdown in the signaling. They have high levels of leptin that aren’t doing a good job of suppressing appetite.

The opposite happens when you lose body fat: Leptin levels drop. This sends a starvation signal to the brain, prompting the metabolic rate to slow and appetite to increase. This was useful during times of famine, but it’s definitely not helpful to people who are trying to maintain weight loss.

In 1999, when a 9-year-old, 208-pound girl with a voracious appetite triggered by leptin deficiency received leptin injections, it was life-changing. Her appetite normalized and she began losing weight.

The study created a splash, but it turns out that leptin deficiency is extremely rare. And leptin injections don’t do anything for the rest of the population with obesity.


What it is: Called the “hunger hormone,” ghrelin is secreted by the stomach when you haven’t eaten for a while, traveling up to the brain where it whets your appetite. It also helps keep things moving through your digestive tract and is involved in the cardiovascular system, immune system, and mental health.

The body weight connection: Just as leptin levels fall with weight loss, ghrelin levels rise, making weight loss all the more challenging.

You’d think that blocking ghrelin would quell appetite and induce weight loss, but ghrelin-blocking medications have had mixed results in animal studies, although the research continues.


What it is: Released by your pancreas in response to the rise in blood sugar (glucose) after eating, this hormone helps spirit away excess glucose into muscle and fat cells. In muscle, glucose is burned as fuel or stored as glycogen. In fat cells, it can be burned, or converted to fat.

The body weight connection: Atkins, keto, and every low-carb diet in between are based on the premise that eating carbohydrates raises insulin levels, which signals the body to store fat. Lose the carbs and you’ll burn more of your body fat, the theory goes.

The problem is, the research doesn’t bear this out. In fact, a National Institutes of Health study pitting a moderate-carb intake (50 percent of calories from carbs) to a very low (5 percent) high-fat diet found that after two weeks people lost more body fat on the moderate-carb plan.

Insulin can be a problem if carrying too much visceral fat. This fat can release inflammatory compounds that make your body less responsive to insulin. Insulin resistance, in turn, appears to trigger more fat storage, in a vicious cycle.

Get a blood test for fasting glucose (sugar) and A1C — a measure of average blood sugar levels over the past few months. As a doctor will explain, a normal fasting sugar is less than 100 mg/dl (milligrams per deciliter), while the range for prediabetes is 101 to 125 mg/dl; and diabetes is greater than 125 mg/dl. An A1C lower than 5.7 or 6.0 percent (depending on the lab) is normal; 6.5 percent or higher is diabetes.

If any of these measurements are too high, a doctor will likely suggest you try losing weight with a sensible nutritious diet and increase your physical activity.

If that doesn’t work, several medications used to treat diabetes also frequently help with weight loss. These medicines reduce heart disease risk as well.


What it is: Dubbed the “stress hormone” because its levels rise with stress, it also brings an immune system and other benefits.

The body weight connection: People with obesity tend to have higher cortisol levels than others. The hormone is also linked to a bigger waistline. Meanwhile, cortisol levels tend to be higher in people under chronic stress — the type that lasts weeks and months.

It’s tempting to connect the dots and say that chronic stress raises cortisol levels, which packs on visceral fat. While there’s some evidence for that, the research is still murky. It could be that stress is simply driving you to overeat, according to experts.

Researchers are investigating medications that may be of value in treating stress-related high cortisol levels as a cause of obesity, but currently, there’s nothing on the market approved for this. For now, if you think you’re under chronic stress, find stress-management techniques that include exercise, meditation, or activities with friends and family.

At our clinic, we are happy to offer the lab evaluation o test the levels of your testosterone and HGH hormones as well as provide replacement therapy if required. For any concerns or for applying for a free consultation, please get in touch.

10 January 2021 Hormones
About Dr. Nil Hoppins

Dr. Nil Hoppins is a consultant dermatologist and professor of medical dermatology specializing in the diagnosis and treatment of skin disorders, treatment of severe scarring, and photodermatology. He has a strong background in translational research, and expertise in genetic skin disorders.

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